Fig. 1

Sample collection locations. Seed was collected from the 249 locations indicated across British Columbia and Alberta, Canada. The average ancestry proportion of individuals in a given collection location is indicated by point color which ranges from blue, representing pure white spruce, to red, representing pure Engelmann spruce. Background colors show predicted species ranges (based on climatic niche model) of white spruce (blue), Engelmann spruce (red) and hybrids (purple). Niche envelopes were generated by Tongli Wang (unpubl.) with methodology as described in Wang et al. [57]. All maps were generated by JD, and produced using ESRI ArcGIS 10.2.2. No copyright permissions were required